PROJECT SUMMARY/ABSTRACT Although there is considerable debate among scientists on both the importance and the generality of different aging mechanisms, in recent years three interrelated perspectives of aging have emerged on which most gerontologists and demographers agree: (1) there are multiple pathways (and thus mechanisms) for attaining exceptional longevity; (2) these pathways have different mortality consequences; and (3) the health of individuals at older ages is conditional on their pathway to these ages. The concept of pathways to old age and their different health costs is foundational to healthy aging outlined in the landmark paper on morbidity compression by Fries (1980) and is also central to this proposed project. One of the fundamental questions that flows from these concepts is whether increasing survival of individuals to advanced ages yields populations that are healthier, or whether these larger fractions arriving at old age means that the average health of the individuals is actually reduced. Whereas this second scenario is referred to as the 'Failure of Success Model', the first scenario is referred to as the 'Success of Success Model'. A less selected group of survivors to old ages may be shaping an older population whole health profile is more diverse relative to earlier populations at the same age. These concepts and models will be used to form the operational framework around which this proposed research project is organized to explore the interplay of geriatric and demography frailty and, in turn, to gain insights into the relationship of health and old-age mortality. Using the Mexican fruit fly (Anastrepha ludens), our broad goal is to bring experimental demography and mathematical models to bear on specific questions concerned with the health and survival of older individuals that experience a wide range of environmental conditions when young. Specific aims include: Aim 1. Identify and calibrate behavioral metrics of health; Aim 2. Health metric measurement and hypothesis testing including assessing health, survival and female reproduction of oldest-old flies maintained different diets (2a) and different reproductive (2b) and stress (2c) conditions; and Aim 3. Statistical modeling and data analysis.